qb79 hpa tank question.

[lillysdad621]

i am trying to get my qb79 to run on HPA. where are you guys getting those 13 ci tanks that come regulated from the factory??? do you guys use a breech raiser, or does it fit under the barrel under the normal thread? are you guys using a 9 oz paintball tank adapter? and finally, what pressure are you guys having the tanks regulated at?... any help will be most appreciated...

[rsterne]

The standard 13 CI HPA tanks are just under 2" in diameter, and will just clear the barrel without any spacers or adapters.... You remove the barrel (so that the fill fitting and gauge can rotate) and screw the tank into the tank block.... basically, that's it, replace the barrel, fill the tank, and shoot....

If you purchase a paintball tank, it SHOULD be regulated to 850 psi, and have a 1.8K burst disc on the downstream (output) side of the regulator.... If the regulator ony has ONE burst disc (it will be a 5K) then it is NOT suitable for use on a QB because if the regulator fails, whatever pressure is in the tank ends up in the gun.... Make SURE that the regulator on your tank has two burst discs, and that the one on the outlet side is 1.8K (1800 psi).... That will limit the pressure to that value if the regulator bypasses....

CO2 can reach 1900 psi at 120*F, so IN THEORY the QB 78 and 79 should be safe at that pressure.... I say in theory, because I know for a fact that at least one QB79 failed when a single burst disc regulator leaked and put 2600 psi into the gun.... The screws securing the tank block to the tube sheared off, the holes in the tube nearly ripped out, and the tank block/regulator/tank assembly blew off the end of the gun and went spinning across the shop floor.... Fortunately, nobody was injured, but it was a wakeup call for those converting QB79s to HPA (or using the QB79 tank block on a 22XX series gun).... There are two problems with the tank block attachment.... First, the screws are a very soft material.... Secondly, the holes are much too close to the end of the main tube.... The first is easy to fix by using high-tensile screws, the second requires drilling another set of holes between the two O-ring positions, adding two more screws, and relying only on the inner O-ring for sealing (which works just fine)....

On my personal guns, I always add the additional two screws, but I run at 1500-1600 psi.... I ALWAYS make sure the gun is protected by a 1.8K burst disc, even with the extra screws.... I have seen lots of QB79s converted to HPA without upgrading the screws, and like I said, in theory it should be fine because the gun should be OK with CO2 at 120*F.... I personally don't think a gun that fails at 2600 psi can be considered safe at 1800 psi, as that is a proven safety margin of less than 1.5:1.... I'm guessing that whoever did the original design used the nominal pressure of CO2 at room temperature (850 psi) to do their safety calculations.... or the design was changed subsequent to the design work.... Lots of people run pressures from 850 to 1200 psi, and as long as the regulator has that 1.8K burst disc on the output they report no problems.... Running above 1200 psi may require shimming the hammer spring or the velocity could very well decrease....

Bob

[lillysdad621]

bob, thank you very much for the explanation. I think i will be happy with about 1200 psi (i already run a qb78 at 1500 and i am happy with the result). i foresee some degree of tuning on the valve and springs, but the purpose is to build a .177 rig that will shoot about 12 fpe. one thing, who sells the tanks? i can't seem to find a link related on the gta mall...

[rsterne]

If you are looking at 12 FPE in .177, you shouldn't need more than 1200 psi, maybe less.... The longest shot string will be found when the hammer strike balances the regulator pressure just as if you were shooting a non-regulated PCP right at the top of the bell-curve.... If you have too much hammer strike you will waste air.... and if you have too little, the velocity will climb below the regulator setpoint....

I haven't done much with QBs in .177 so I can't advise specific setups.... Ninja is the best source of tanks, and they are usually all over eBay at good prices, but right now I don't see any....

Bob

[lillysdad621]

bob: thanks for all your help. If i run a 850 psi regulated bottle i should have a very long shot string that should be fairly consistent UNTIL the pressure on the gauge goes under 850, correct?
John: It is that FT rig on the rail that has been haunting me all this time!!!! that is exactly what i want to accomplish.... 850 psi will do then.

[rsterne]

Yes, the velocity should be relatively consistent until the tank pressure drops below 850 psi.... If you notice, that valve on the 850 psi FT rig is extensively modified.... I don't know if you can get 12 FPE in .177 without following suit.... However, you could get that power level with a stock valve (maybe the screen and filter removed) at a higher pressure, certainly by the time you get to 1200 psi.... I was getting 15 FPE in .22 cal at 1100 psi with the only mods being a poly transfer port and the filter removed from the valve....

There are lots of ways to get to a given power level.... The better you make a gun breathe (both into and out of the valve) the lower the pressure required to achieve a given FPE.... You can obviously do it at 850 psi with a modded valve.... you can also do it with a stock valve and a bit more pressure....

Bob

[lillysdad621]

then i'll get a 1200 psi regulated tank... i can do mild modifications to the valve, but nothing like the picture. Filter off, yes, valve pin polished yes, larger port, moly tubing, angle port and bolt probe mod i can tackle.

[rsterne]

It's pretty easy to adjust the regulator output downwards if you start with a 1200 psi Ninja (which uses belleville washers - ie disc springs).... much easier than going up from an 850 psi which uses a coil spring.... Here is a chart you may find helpful....



That only applies to Ninja regulators, and it was only accurate for my particular regulator.... However, I think you will find that the shim thickness will be within about 0.010" and the trends will be valid.... The Ninja regulators use ten 0.032" thick bellevilles plus 1 or 2 thinner ones (0.022") on the ends.... plus flat shims.... The bellevilles are arranged as follows:

) ) () () () () ( ( | |

Bold type equals thick, normal type equals thin.... You shouldn't need to touch the valve port or stem for those power levels.... HTHs.... MAKE SURE you have a 1.8K burst disc on the output side of the regulator....

Bob

[lillysdad621]

most of the times i only see one burst disc on them. do you have to request another one installed?

[rsterne]

ALL Ninja regulators have two burst discs.... DO NOT use a regulator with a single burst disc on a QB79.... If the regulator fails when you have 3000 psi in the tank, you will end up with 3000 psi in the gun.... for a brief moment until it blows the tank block off the end.... NOT a good idea....

Bob

[Scott Endler]

So which is the easiest 13 ci regulated hpa bottle and regulator to set to 1400 psi for use under my Challenger or PRod? I like the new Guerrilla Myth regulator in a bottle for only $55 but don't know if it can be dialed up that high. The Ninja Pro SHP should work but costs a bit more to get into.
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And, what happened to the 22 ci hpa bottles. They came and went.

[Scott Endler]

The price at Archer might not be too much higher than ebay.
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http://www.@#$%^.com/Regulated-HPA-Tank-for-QB79-and-QB79-Repeater-p/ninjapro13shp.htm
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[Scott Endler]

Well. I see one particular vendor must have made enemies here.

[nervoustrigger]

The 13ci SHP bottle is also available from Wicked Sports if you don't want to use the other guy.

As far as meeting a 12fpe power level, a QB79 in .177 can do that on 850psi if it is opened up to breathe well.  It will be easier with a little more pressure behind it though.  I've bumped a couple of the standard bottles up from 850 to 1000psi recently by adding a single 0.022 Belleville.  The 79 is making 15fpe and a 78 is making 17fpe.

I don't know how far you can push them before they fall out of regulation but based on the work of others, I'm not inclined to go above 1000psi.

[Scott Endler]

The Ninja SHP Pro seems to be the one to go for since it starts at 1100 psi stock and has been shown to go up from there. One user here is running all the way up to 1500 with a change of one washer. There is a good thread here with shim part numbers from McMaster Carr and diagrams of the installation position.
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http://www.gatewaytoairguns.org/GTA/index.php?topic=49648.0
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[Maher1510]

The Ninja SHP is the one i have on my QB79 and with that regulator it spins so you don't have to take the barrel off to put it on. Got mine off eBay .

[wilsonj1018]

shp 1100 psi on 13ci will make 20fpe in .177 if you port enough

[Gunut]

I got my hpa tank from the verboten dealer. It is on a AR79 B. Stock block.  3000 psi reg to 1100.

[sr1sws]

The 13ci SHP bottle is also available from Wicked Sports if you don't want to use the other guy.

As far as meeting a 12fpe power level, a QB79 in .177 can do that on 850psi if it is opened up to breathe well.  It will be easier with a little more pressure behind it though.  I've bumped a couple of the standard bottles up from 850 to 1000psi recently by adding a single 0.022 Belleville.  The 79 is making 15fpe and a 78 is making 17fpe.

I don't know how far you can push them before they fall out of regulation but based on the work of others, I'm not inclined to go above 1000psi.

Got mine from Wicked.  They are in Tampa, where I live - so I was able to drive by and snag one.  Nice guys and they have a nice shop full of paintball equipment.

Steve